From 44f419264898f84fe5536f3ea159c18b381e6083 Mon Sep 17 00:00:00 2001
From: Adrian Kummerlaender
Date: Sun, 16 Apr 2017 13:17:22 +0200
Subject: Extract variable management, move into `state` package

---
 source/state/definition.d | 84 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)
 create mode 100644 source/state/definition.d

(limited to 'source/state/definition.d')

diff --git a/source/state/definition.d b/source/state/definition.d
new file mode 100644
index 0000000..ab100d5
--- /dev/null
+++ b/source/state/definition.d
@@ -0,0 +1,84 @@
+module state.definition;
+
+import std.string;
+import std.variant;
+import std.typecons;
+
+import std.container : DList;
+
+import state.stack;
+
+alias Words = Stack!Token[string];
+
+Words words;
+
+bool handle(Token token) {
+	return token.visit!(
+		(int    value) => handle(value),
+		(bool   value) => handle(value),
+		(string word ) => handle(word)
+	);
+}
+
+Stack!Token get(string word) {
+	if ( word in words ) {
+		return words[word].dup;
+	} else {
+		return Stack!Token(Token(word));
+	}
+}
+
+private {
+
+Nullable!(DList!Token) definition;
+
+void register(DList!Token definition) {
+	string wordToBeDefined;
+
+	definition.front.visit!(
+		(int    value) => wordToBeDefined = "",
+		(bool   value) => wordToBeDefined = "",
+		(string name ) => wordToBeDefined = name
+	);
+
+	if ( wordToBeDefined == "" ) {
+		throw new Exception("words may not be numeric or boolean");
+	}
+
+	definition.removeFront;
+	words[wordToBeDefined] = Stack!Token(definition[]);
+}
+
+template handle(T)
+if ( is(T == int) || is(T == bool) ) {
+	bool handle(T value) {
+		if ( definition.isNull ) {
+			return false;
+		} else {
+			definition.insertBack(Token(value));
+			return true;
+		}
+	}
+}
+
+bool handle(string word) {
+	if ( definition.isNull ) {
+		if ( word == "§" ) {
+			definition = DList!Token();
+			return true;
+		} else {
+			return false;
+		}
+	} else {
+		if ( word == ";" ) {
+			register(definition);
+			definition.nullify;
+		} else {
+			definition.insertBack(Token(word));
+		}
+
+		return true;
+	}
+}
+
+}
-- 
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